[Opensg-users] Adding and removing material textures

[Glyn Matthews]

Hi all,


I'm working on a 3D project which uses OpenSG, and I'd like to know if there is an efficient way of adding and removing materials (in fact I'm using SimpleTexturedMaterial) in a way such that a texture can be toggled on or off.

The 3D data is reconstructed from 2D images and I want to toggle a texture on a model so its possible to view the 3D data with the overlayed image or without so its possible to visualise the quality of the reconstruction.  Currently I'm doing the following:


  void OpenSGWidget::removeTexture(NodePtr &node)
  {
    GeometryPtr geo(GeometryPtr::dcast(node->getCore()));
    if (geo == NullFC)
      return;

    MaterialPtr mat = geo->getMaterial();
    if (mat != NullFC && mat->getType().isDerivedFrom(SimpleTexturedMaterial::getClassType()))
    {
      material_ = SimpleTexturedMaterialPtr::dcast(geo->getMaterial());
      addRefCP(material_);
   
      SimpleMaterialPtr simplemat = SimpleMaterial::create();
      beginEditCP(simplemat);
      simplemat->setDiffuse(Color3f(.9,.9,.9));
      endEditCP(simplemat);
   
      beginEditCP(geo, Geometry::MaterialFieldMask);
      geo->setMaterial(simplemat);
      endEditCP(geo, Geometry::MaterialFieldMask);
    }
  }
 
 
  void OpenSGWidget::addTexture(NodePtr &node)
  {
    GeometryPtr geo(GeometryPtr::dcast(node->getCore()));
    if (geo == NullFC)
      return;

    if (material_ != NullFC)
    {
      SimpleMaterialPtr simplemat = SimpleMaterialPtr::dcast(geo->getMaterial());

      beginEditCP(geo, Geometry::MaterialFieldMask);
      geo->setMaterial(material_);
      endEditCP(geo, Geometry::MaterialFieldMask);

      if (simplemat != NullFC)
    subRefCP(simplemat);

      subRefCP(material_);
      material_ = NullFC;
    }
  }


OpenSGWidget is a QT widget, material_ is a local field that stores a pointer to the SimpleTexturedMaterial object.

The problem with this approach is that for large models, it is extremely slow and can take between 5 and 20 seconds to re-render.  The delay occurs in the following function:

  void OpenSGWidget::paintGL()
  {
    mgr_->redraw();
  }

mgr_ here is a SimpleSceneManagerPtr.

Is there a way to efficiently toggle a texture in this way?

Thanks in advance,
Glyn Matthews

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